Requires: If a unit “requires” another unit, it means that the former cannot function properly without the latter being active. If the required unit fails, the dependent unit will also fail.
Wants: As mentioned earlier, “wants” implies a weaker dependency. If a unit wants another unit, it will start if the wanted unit is activated, but it won’t fail if the wanted unit fails.
Sounds like most of the services actually have Requires and not Wants.
So Wants is more used to indicate in what “wave” a service should run. Quite nice!